The present invention relates to an automatic packing and sealing apparatus, wherein a plastic film drum with plastic film is placed on a first roller shaft and a second roller shaft and between two adjusting sleeve members freely slidably fitted on the second roller shaft, whereby the placement of the plastic film is easy and the position thereof is adjustable. A substantially U-shaped stretching lever is disposed for forcing open the plastic film against the attaching force so as to facilitate the transferring and packing of the plastic film. A blowing tube is diagonally fixed on a frame body under a front conveying belt assembly, whereby an operator is able to blow diagonally inwardly into the plastic film to expand the same permit an article on the front conveying belt assembly to be packed closer to a film-sealing position so as to save material and make the package more impacted. Activating plates are disposed on two sides of the sealing blades, whereby during the conveying process, if the article does not completely pass through the sealing blade or the operator incautiously extends his hand into a position under the sealing blades, before the sealing blades touch the article, the activating plates will first touch the article and be moved upward, so that the sensing plates connected with the activating plates will ascend along therewith and interrupt sensing switches so as to emergently stop the packing and sealing apparatus for ensuring the safety of the operator, reducing loss of the article and prolong the using life of the packing and sealing apparatus.
The conventional packing and sealing device is shown in FIGS. 1 and 2. Such packing and sealing device includes mainly a plastic film-feeding system 1, a packing system 2, a sealing system 3 and a transferring system 4, wherein as shown in FIGS. 3 and 4, the plastic film-feeding system 1 includes a feeding roller shaft 11, a clamping roller shaft 12 and a tension-adjusting shaft 13. The feeding roller shaft 11 is fixed on two shaft seats 14 and provided with two fixing means 111 for clamping a plastic film drum 5 fitted on the feeding roller shaft 11. Two swinging arms 15 are disposed on two sides of the tension-adjusting shaft 13 and a guiding rod 16 is connected at the ends of the swinging arms 15. A tension-adjusting thread rod 131 is disposed on the tension-adjusting shaft 131 and an adjusting block 132 is screwed with the thread rod 131.
The above arrangements are operated in such a manner that when starting the packing and sealing device, the feeding roller shaft 11 is first taken out and one of the fixing means 111 is detached. Then, the plastic film drum 5 is installed onto the feeding roller shaft 11 and the fixing means is fitted thereon to secure the plastic film drum 5. Thereafter, the plastic film is pulled out of the drum 5 to wind through the clamping roller shaft 12 and the tension-adjusting shaft 13 toward the sealing blades. To keep a suitable tension of the plastic film with respect to different sizes of articles to be sealed so as to facilitate the sealing operation, the tension of the plastic film is controlled by moving the adjusting block 132 of the tension-adjusting thread rod 131.
However, above feeding roller shaft 11 and tension-adjusting shaft 13 have several shortcomings as follows:
1. The plastic film drum 5 is fixed on the feeding roller shaft 11, so that when the plastic film is used up, the feeding roller shaft 11 and the fixing means 111 thereof must be detached for taking out the empty drum and installing a new one onto the feeding roller shaft 11. Then, the new drum is clamped by the fixing means 111 for further operation. Such procedure is troublesome and time-costing. PA1 2. During the feeding of the plastic film, the drum 5 continuously abrades against the feeding roller shaft 11. Therefore, the drum is liable to be worn out and make the feeding of the plastic film unstable. PA1 3. The tension of the plastic film is controlled by the adjusting block 132 of the tension-adjusting thread rod 131 of the tension-adjusting shaft and the entire tension-adjusting means is located in the plastic film-feeding system 1. Therefore, for ensuring the safety, when adjusting the tension of the plastic film, the device must be first stopped and then the adjusting block 132 can be adjusted for controlling the tension of the plastic film. Such stopping, adjusting, starting and testing procedures are repeatedly performed until the tension of the plastic film is correct. The above procedures are time-costing and labor-wasting. PA1 4. The above adjusting operation is performed by way of varying the eccentric distance and the weight of the adjusting block 132. In case the plastic film is fed at varying speeds or intermittently during the feeding process, the guiding rod is apt to vibrate and the tension of the plastic film can hardly be constant. As a result, the feeding, packing and sealing operations cannot be performed stably. PA1 1. The plastic film is placed on a first and a second roller shafts and clamped by two adjusting sleeve members of the second roller shaft, so that after the plastic film is used up, the plastic film drum can be replaced by a new one without detaching the roller shafts or fixing means. Therefore, the replacement of the plastic film is easy and the position of the plastic film drum can be adjusted during the operation of the apparatus without stopping the same. PA1 2. The tension of the plastic film is contolled and adjusted directly by the tension-adjusting shaft without stopping the operation so that the time and labor are saved. PA1 3. A coil spring is used to control and adjust the tension of the plastic film, so that the vibration thereof is eliminated and the tension of the plastic film is kept constant during the feeding procedure. Therefore, the sealing operation can be performed smoothly. PA1 4. The plastic film is wound through a stretching rod and a substantially U-shaped stretching lever which force open the plastic film against the attaching force and facilitate the transferring and packing of the plastic film. PA1 5. A blowing tube is diagonally fixed on a frame body under a front conveying belt assembly, whereby an operator is able to blow air diagonally inwardly into the plastic film to expand the same and permit an article on the front conveying belt assembly to be packed closer to a film-sealing position so as to save material and make the package more impacted. PA1 6. Activating plates are disposed on two sides of the sealing blades, whereby during the conveying process, if the article does not completely pass through the sealing blade or the operator incautiously extends his hand into a position under the sealing blades, before the sealing blades touch the article, the activating plates will first touch the article and be moved upward, so that the sensing plates connected with the activating plates will ascend along therewith and interrupt sensing switches so as to immergently stop the packing and sealing apparatus for ensuring the safety of the operator and reducing loss of the article.
Please further refer to FIG. 5. The plastic film is fed by the feeding system 1 and turned and guided by the guiding rod 19 into the packing system 2 in a double folded pattern. The packing system 2 of the conventional packing and sealing device includes a conveying platform 21 and an upper and a lower triangular turning guiding boards 22, 23, whereby an upper sheet of the folded plastic film goes through the upper guiding board 22 and turns 90 degrees, while the lower sheet thereof goes through the lower guiding board 23 and turns 90 degrees. Therefore, the upper and lower sheets are 90 degrees turned by the upper and lower triangular guiding boards 22, 23 and meet at a transverse sealing blade 31 of the sealing system 3. The lower guiding board 23 is fixed, while the upper guiding board 22 is fixed on an adjustable support 24 which can be vertically moved by rotating a wheel 26 to drive a thread rod 26 so as to meet the requirement of different sizes of articles.
As shown in FIG. 7, the article is packed in such a manner that the article is conveyed to a position under the upper turning guiding board 22 by means of the conveying platform 21. (The level of the upper turning guiding board 22 can be controlled by the adjustable support 24 so as to adjust the distance between the conveying platform 21 and the upper turning guiding board 22, making the article pass therethrough smoothly.) When the article goes between the conveying platform 21 and the upper turning guiding board 22 and is spaced from the transverse sealing blade 31 by a certain distance, the sealing blade 31 will be pressed down to thermally seal a front end portion of the plastic film in front of the article. At this time, the lateral open ends of the plastic film 5 are clamped on a clamping/feeding chain assembly 40 and the same continuously clamps and pulls the plastic film forward. Therefore, the plastic film 5 and the article will go forward simultaneously and pass through the transverse sealing blade 31. After a rear end of the article passes through the sealing blade 31 for a certain distance, the sealing blade 816 is again pressed down to seal the rear and lateral ends of the plastic film 5 and thus make the article totally sealedly enveloped by the plastic film 5 and complete the packing and sealing process.
The above packing and sealing operation has a serious problem that when the article is transferred by the conveying platform 21 under the upper guiding board 22, because the plastic film is soft and is difficult to be deformed according to the shape of the article, the corners of the article are apt to engage with the plastic film. (The larger the article is, the more serious the situation is.) Therefore, the plastic film is likely to deform or break and the package will be crimped. In addition, excessive plastic film will be wasted.
Moreover, as shown in FIGS. 6 and 7, the transverse and longitudinal sealing blades 31, 30 are fixed above the upper swinging arm 32 and sealing blade seats 34 are disposed above the lower swinging arm 33. Multiple support rods 341 are fixed under the sealing blade seats 34. A spring 342 is fitted on the support rod 341 which extend through the lower swinging arm 33 to be secured by nuts 343 so as to buffer the vertical reciprocating movement of the sealing blade seats 34. Such structure can only achieve the object of sealing the plastic film, while it is possible that the article does not completely pass through the transverse sealing blade 31 or the operator incautiously extends his hand into a position under the sealing blade. At this time, no safety device is provided to emergently stop the sealing system for ensuring the safety of the operator, reducing loss of the article and protect the packing and sealing apparatus.